Returning a Refurb Nikon

I bought a refurb D800E less than a week ago. I am slowly realizing that I may have bought the wrong camera for my intended purposes. I really love low light photography and find that I really need to pump up the ISO to achieve sharp photos in low light and the high iso ability on the d800 is not great. Has anyone successfully returned a refurb bought from Nikon? They say they will only accept a return if the camera is defective. Any ideas?